scholarly journals Analyses of Hydrodynamic Radial Forces on Centrifugal Pump Impellers

1988 ◽  
Vol 110 (1) ◽  
pp. 20-28 ◽  
Author(s):  
D. R. Adkins ◽  
C. E. Brennen
Keyword(s):  
Theoretical Model ◽  
Centrifugal Pump ◽  
Substantial Effect ◽  
Operating Conditions ◽  
Pump Impeller ◽  
Pressure Distributions ◽  
Flow Disturbances ◽  
Radial Forces ◽  
Flow Through ◽  
Centrifugal Pump Impeller

Hydrodynamic interactions that occur between a centrifugal pump impeller and a volute are experimentally and theoretically investigated. The theoretical analysis considers the inability of the blades to perfectly guide the flow through the impeller, and also includes a quasi-one dimensional treatment of flow in the volute. Flow disturbances at the impeller discharge and the resulting forces are determined by the theoretical model. The model is then extended to obtain the hydrodynamic force perturbations that are caused by the impeller whirling eccentrically in the volute. Under many operating conditions, these force perturbations were found to be destabilizing. Comparisons are made between the theoretical model and the experimental measurements of pressure distributions and radial forces on the impeller. The theoretical model yields fairly accurate predictions of the radial forces caused by the flow through the impeller. However, it was found that the pressure acting on the front shroud of the impeller has a substantial effect on the destabilizing hydrodynamic forces.

Theoretical Analysis of Flow Through Two-Dimensional Centrifugal Pump Impeller by Method of Singularities

1971 ◽  
Vol 93 (1) ◽  
pp. 35-40 ◽  
Author(s):  
S. K. Ayyubi ◽  
Y. V. N. Rao
Keyword(s):  
Centrifugal Pump ◽  
Operating Conditions ◽  
Two Dimensional ◽  
Pump Impeller ◽  
Pump Operation ◽  
Wide Range ◽  
Hydrodynamic Method ◽  
Flow Through ◽  
Experimental Values ◽  
Centrifugal Pump Impeller

The hydrodynamic method of singularities is used to analyze the flow through two-dimensional centrifugal pump impellers with blades of an arbitrary geometry. Computed values of ideal head are compared with experimental values obtained for a commercial pump. The agreement between theory and experiment is very close over a wide range of pump operation. The discrepancies that occur at other operating conditions are attributed to the effects of inlet passage and volute casing.

Theoretical Investigation of Pressure Distributions Along the Surfaces of a Thin Blade of Arbitrary Geometry of a Two-Dimensional Centrifugal Pump Impeller

1977 ◽  
Vol 99 (3) ◽  
pp. 531-539 ◽  
Author(s):  
T. C. Mohana Kumar ◽  
Y. V. N. Rao
Keyword(s):  
Centrifugal Pump ◽  
Numerical Procedure ◽  
Two Dimensional ◽  
Arbitrary Geometry ◽  
Pump Impeller ◽  
Pressure Distributions ◽  
Blade Thickness ◽  
Hydrodynamic Method ◽  
Flow Through ◽  
Centrifugal Pump Impeller

The flow through a two-dimensional centrifugal pump impeller with thin blades of arbitrary geometry is investigated using the hydrodynamic method of singularities. A theoretical analysis is developed to determine the impeller head and pressure distributions along the blade surfaces. The convergence of the numerical procedure is discussed. These results are compared with the theoretical and experimental results reported by Acosta. There is excellent agreement between the theoretical values of the impeller head and the pressure distributions obtained by both methods. Discrepancies in the theoretical and experimental pressure distributions are attributed to the effects of viscosity, inlet turn, blade thickness and inlet stall which are neglected in the analysis.

scholarly journals Some Unsteady Fluid Forces on Pump Impellers

1992 ◽  
Vol 114 (4) ◽  
pp. 632-637 ◽  
Author(s):  
R. S. Miskovish ◽  
C. E. Brennen
Keyword(s):  
Fluid Flow ◽  
Centrifugal Pump ◽  
Bending Moments ◽  
Pump Impeller ◽  
Spectral Analyses ◽  
Fluid Forces ◽  
Radial Forces ◽  
Unsteady Fluid ◽  
Rotordynamic Forces ◽  
Centrifugal Pump Impeller

Spectral analyses of all the forces and moments acting on a typical centrifugal pump impeller/volute combination are presented. These exhibit shaft frequencies, blade passing frequencies, and beat frequencies associated with a whirl motion imposed on the shaft in order to measure rotordynamic forces. Among other features the unsteady thrust was found to contain a surprisingly large blade passing harmonic. While previous studies have explored the magnitudes of the steady fluid-induced radial forces and the fluid-induced rotordynamic forces for this typical centrifugal pump impeller/volute combination, this paper presents information on the steady bending moments and rotordynamic moments due to the fluid flow. These imply certain axial locations for the lines of action of the radial and rotordynamic forces. Data on the lines of action are presented and allow inferences on the sources of the forces.

Numerical and Experimental Investigations of the Cavitating Flow in a Centrifugal Pump Impeller

2002 ◽  
Author(s):  
Moritz Frobenius ◽  
Rudolf Schilling ◽  
Jens Friedrichs ◽  
Gu¨nter Kosyna
Keyword(s):  
Numerical Simulations ◽  
Centrifugal Pump ◽  
Bubble Dynamics ◽  
Cavitating Flow ◽  
Experimental Investigations ◽  
Pump Impeller ◽  
Pump Head ◽  
Flow Through ◽  
Technical University ◽  
Centrifugal Pump Impeller

This paper presents numerical simulations and experimental investigations of the cavitating flow through a centrifugal pump impeller of low specific speed. The experimental research was carried out at the Pfleiderer-Institute of the Technical University of Braunschweig, while the numerical simulations were performed at the Institute for Hydraulic Machinery and Plants at the Technical University of Munich (LHM). The cavitation model used is based on bubble dynamics and is able to describe the complicated and transient growth and collapse of the cavitation bubbles. The model has been implemented in the 3D CFD-code CNS3D developed at the LHM. The CNS3D-code has been applied to simulate the cavitating flow through a centrifugal pump impeller. The computed pump head, incipient NPSH and three-percent head drop are compared to the experimental data. Also the pressure distributions measured on the blades are compared with the computed ones. Finally, the numerically investigated void fraction distributions are shown in comparison with pictures of the cavitation zones on the blade.

Measurements of Rotating Stall Inside a Centrifugal Pump Impeller

2005 ◽  
Author(s):  
D. A. Johnson ◽  
N. Pedersen ◽  
C. B. Jacobsen
Keyword(s):  
Centrifugal Pump ◽  
Marked Change ◽  
Rotating Stall ◽  
Velocity Measurements ◽  
Pump Impeller ◽  
Pressure Transducers ◽  
Design Load ◽  
Measured Flow ◽  
Flow Through ◽  
Centrifugal Pump Impeller

Velocity measurements have been obtained in a centrifugal pump with a volute. The measurements have been obtained between the blade passages of a shrouded impeller and in the volute region using laser Doppler velocimetry (LDV). Complimentary measurements have been obtained with pressure transducers circumferentially mounted on the volute. The flow through the impeller is measured at both design load and at several off-design conditions including severe off-design conditions. Results show that flow behaviour at design conditions Qd is well behaved. At reduced flow off-design conditions (0.25Qd) the measured flow pattern was altered significantly showing alternating stable stationary stalled and unstalled passages. Spectral analysis of the data from the LDV probe and the pressure probes showed a marked change in the spectrum as the stall phenomena occurs. This result is in contrast with previous researchers who have reported partially stalled flow passages or rotating stall conditions where the stall pattern rotated relative to the impeller with a regular frequency.

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